Spark plug



May 29, 1492s.

J. R. BALDWIN, JR., ET AL SPARK PLUG Filed Ap'ril 26,

@Wm new Patented May 29, 1928.

UNITED STATES .PATENT` OFFICE.

JOHN BOY BALDWIN, JR., .AND ROBERT WALTER SCHAEFER, OF LOUISVILLE, i

KENTUCKY.'

SPARK PLUG.

, Application led April 26, 1924. Serial No. 709,189.

This invention relates to improvements in spark plugs and more particularly to a type of spark plug which will have its electrodes v positioned well interiorly of its body portion and which will be provided with suitable means whereby the said electrodes may be readily and quickly cleaned.

An object of the invention is to provide a spark plug wherein the electrodes are posltioned in a sparking chamber intermediate the ends of the body of the spark plug in order to prevent, as far as possible, the deposit on the electrodes of linely divided particles of carbon and insulating solid 1mpurities, resulting from imperfect combustion and held in suspension in the exhaust gases after combustion. By removing the electrodes as far as practicable both from combustion in the cylinder and from the onrush of the products of combustion as these latter are forced toward the exhaust port after explosion, the necessity for cleaning electrodes is reduced to the minimum.

A further object of the invention is to provide a spark plug which will be formed with one or more openings through its body portion whereby the electrodes of said spark plugs will be readily and eiiiciently cleaned, and to further provide a removable closure which will normally be positioned over said openings to completely seal the same when the spark plug is in use.

Other objects will appear as the description proceeds.

In the accompanying drawings which form a part of our application,

Figure 1 is a. sectional view taken through our improved spark plug, and

Figure 2 is a transverse sectional view taken on the line 2-2 of Figure 1.

Like characters of reference yare used throughout the following speciication and the accompanying drawings to designate corresponding parts.

Our improved spark plug comprises a hollow nut or body portion 1, which is provided with an externally threaded portion 2 at its lower end, the same being adapted to thread into an engine cylinder.

One or more tool ports or openings 3 are formed through the central part of the body portion 1, and are normally sealed by means of a removable nut 4, which i-s threaded at 5 on to the central part of the said body. Asr seen from the drawings the threaded portion 5 of the body 1 is greater in size or diameter than the threaded portion 2 of the said body.

' The body portion 1 is further provided with an internal ring or seat 6, and is adapted to support the annular rim or bead 7 of the insulator 8, which is adapted to be securely held in place by means of the threaded lock nut 9, the same being adapted to securely seat down on the upper surface of the said rim or bead 7.

A centrally disposed electrode 1() is positioned through the said insulator 8 and extends a short distance below the bottom thereof. The upper end of the electrodeis threaded at 11 and is adapted to receive a binding post cap or nut 12. A Isecond electrode 13 extends out at right angles from the inner wall of the body portion 1 to a point adjacent the lower end of the said electrode 10.

When it is desired to clean the plug after the same has become foul, it is only necessary to remove the plug :from the cylinder head and with a pair of wrenches unscrew and remove the nut 4, whereupon ready access may be had to the openings 3 which are directly in aline with the adjacent ends of the electrodes 10 and 13. The electrodes may then be carefully cleaned by means of a wire brush or other suitable device, after which the nut 4 may be replaced to completely seal the openings 3, and the plug replaced in the cylinder head.

From the foregoing description it will be apparent that many minor changes in detail of construct-ion may be resorted to without departure from the spirit of the invention.

We claim:

A spark plug comprising a hollow cylindrical body with one end open and exteriorly threaded to seat in the cylinder head of an internal combustion engine, and with the other end interiorly threaded and normally sealed with a removably secured insulator plug, and with the portion intermediate the threadings of its ends enlarged and provided interiorly with a sparking chamber communicating with. the cylinder through the said open body end, the combination therewith of an electrode positioned within said sparking chamber axially secured within said insulator plug and exteriorly adapted to connect with a source of electric current, a zo-acting electrode adjacent the first menlll tionedfeleetrodeand seeuredto the inner Wall ofthe said body, anintermediate` portion of the said body adjacent said spark-`4 ing chamber. ezteriorly threaded and pro.

vided fwith diametriealiy opposed portsl` 1ocated opposite said electrodes to provide a straight passage through said body andthe said sparking chamber and adapted for insertion and passage thrlgiiltlef chamberoi lo tools, abrasive cloth or the like for cleaning toseal them during explosion. 15

In testimony whereof We aiX our signa- 'JOHNRYQ'BALDWIM JR.

ROBERT WALTER SCHAEFER, 

